The Mars rover Opportunity has discovered what scientists say is the first meteorite of any type ever identified on another planet.
Opportunity encountered the basketball-sized hunk of iron and nickel during a study of its landing site in the Meridiani Planum region and used its onboard instruments to confirm the meteorite's origins, principal scientist Steve Squyres said Wednesday.
"We have been driving around on the plain seeing lots of little rocks the size of a fist or a potato -- we call them cobbles," Squyres said. "Now we're not so sure they're just lumps of rock. Suppose they are meteorites?"
If the cobbles are meteorites, scientists would then begin probing whether martian winds are depositing sand on the planet's surface or scouring the surface to reveal rocks.